Do you want a complete guide on the glove valve? Do you want to know the working advantages or disadvantages of the globe valve? In different industries and residential applications, the used thing is valves. The valves have various functions, such as being used to control the flow of fluid. Many types of valves are used for different purposes. But in this guide, we will describe the globe valve. In this article, we will discuss the advantages and disadvantages of globe valves. It is a linear flow valve that starts, stops, or regulates fluid flow. They have more pressure drop than gate valves.

Globe valves are smooth or flat motion valves most employed to start, stop, and throttle flow. Their structure looks like a stem that moves up and down to control flow inside the valve. The system includes a disc plug and seat commonly tightened into the valve body. Seats produce in an inclined plane or parallel to the flow line. These control valves are most often used to open or close the flow valve throttle in a system. The disk of a globe valve can be drawn entirely from the flow path, or it can completely close the flow path.

Traditional Globe valves may be used for throttling and isolation services. Although these valves display little higher pressure drops than straight-through valves

Construction of a Globe Valve And Working Principles

The construction of the globe valve body includes a bonnet, disc/plug, and stem. The opening and closing parts of the globe valve are round discs, the flat sealing surfaces. The valve’s stem shifts up and down by the hand wheel to remain at its location. 

Globe valves often have moving stems, and the larger sizes are of the outside screw. This valve has seats in a parallel plane or inclined to the flow line. This valve is only used for a completely open and closed system. The globe valve is force-sealed. Pressure must apply to the disc to maintain tight sealing while closing the valve. 

The working force must handle the resistance when the fluid moves the valve from below the disc. When the pressure for the closing valve is greater then the force to open the valve also increases to prevent the stem from bending.

With a pressure seal globe valve, the medium flow direction is changed to the cavity from above the valve disc. In the same situation, the pressure of the medium will close the valve to decrease. And when the force of opening the valve increases, it can reduce the stem diameter. 

Working of Globe Valve

1. We have explained above that the globe valve is unidirectional. You can establish it in only one direction. It includes a disc, hand wheel, or stem and plug. The globe valve starts, regulates, and stops the flow of liquid. 
2. The globe valve works in the below-explained pattern. An operator regulates, opens, and closes, the flow by turning the valve’s hand wheel.
3. The hand wheel combines with the stem and is connected to the valve disc. To open the valve, the operator moves the hand wheel in an anticlockwise direction.
4. In such a direction, the stem removes the disc from the two valve seats and pulls the valve disc.
5. For throttling flow, the operator moves the wheel in which direction the valve disc opens and closes.
6. To reduce or lower fluid flow, the operator moves the wheel clockwise in a clockwise direction.
7. Then, the handle transfers its downward motion to the stem.
8. After the stem gets handwheel motion, it pushes and moves downward and the valve disc downward.
9. This downward motion of the valve disc usually fits it between the two seats of the valve and stops the fluid flow.

Advantages and disadvantages of Globe valves

Advantages:

• Good shutoff capability
• Moderate to good throttling capability
• Available in different abilities, wye, and angle patterns, each offering unique capabilities
• Easy to resurface the seats
• Leakage and conform to international sealing standards.
• Globe valve can be used as a stop-check valve when the disc is not attached to the stem.
• The structure of the globe valve is easy to install and convenient for maintenance.
• Reduce energy loss and fluid loss, and improve plant tools safety.
• Long service life, fewer keeping times, and lower operating costs
• A robust bellows seal design ensures zero leakage of the valve stem and offers maintenance-free conditions.
• The opening and closing time is short because the working stroke is minor compared to the gate valve.
• Small friction, good sealing between sealing surfaces, long life
• The structure of the Globe Valve body is direct-flow and right-angle. Fluid resistance is the greatest, but the DC fluid resistance is small and used for fluids with high viscosity. The right-angle valve body is mainly developed and suitable for high-pressure shutoff valves.
• The bellows sealing globe valve is designed with bellows which completely removes the common issues of valve stem packing seal, which is aging fast and accessible to leaks. It not improves energy efficiency and also increases the safety of the equipment. It also reduces costs and also provides a clean and safe working environment

Disadvantages:

• The change performance of the valve is poor.
• It is not suitable for media that have high viscosity.
• These valves have throttling flow under the seat and shutoff flow over the seat.
• The significant fluid resistance and the large force required for opening and closing.
• Requires greater force to seat the valve.
• The main disadvantage is that these valves create a more significant head loss. In other words, head loss also refers to pressure loss. The pressure loss is the amount of resistance a liquid has as it flows by pipes. More pressure loss occurs when there is more resistance. Turbulence, gravity, friction, or the moving fluid against the pipe walls cause heat loss. Valves and fittings lead to the loss of pressure mainly through turbulence.

Under Which Condition Glove Valves are Used?

When to use globe valves

The globe valve is operated often for throttling flow control. The shutoff is achieved by directing the disc against the flow stream instead of across it. Close-off is obtained by changing the disk against the flow stream rather than in the fraction using a bent valve. The moving way of a globe valve will lead to more excellent resistance to flow, resulting in high-stress fall.

The flow causes a high-pressure drop when greater resistance occurs in direction. So, the globe valve is an ideal choice to use in high-pressure working steam.

Globe valves are also used to control the liquid flow through a pipeline. They may be utilized to stop the fluid flow altogether, allow slowing it down or permit the fluid to flow freely. The body of globe valves is globe-shaped, a level piece plus a bit fit to stop the fluid stream. Whenever you want to modulate flow, Globe valves are the ideal choice. Some applications include:

• Fuel oil systems
• Chemical feed systems
• Cooling water systems
• Turbine lubricating oil systems
• Drain applications in fire sprinklers 
• Other water-based fire protection systems

Why is it called a Globe Valve?

• If you want to know why it is called a globe valve? Check the below points:

• The older designs can be divided into two main parts and resemble a globular structure in the shape of hemispheres.

• The direction of flow changes when the equator separates hemispheres.

• But, the main internal component that limits fluid flow in the valve is not spherical.

• Those parts are more like, semi-spherical, flat, plug shapes.

• Globe valves are comparatively more resistant to the flow than other valves, which results in higher pressure.

What Role Plays In A Globe Valve?

1. The essential function of globe valves is to start or stop and regulate fluid flow.
2. It is used in water and chemical supply systems
3. They are specially designed to control fluid flow and shutoff functionality.
4. Shutoff valves are used in compressors.
5. It is also used in condensate extraction and exhaust systems.
6. These valves are used in central steam vents, drain systems, and heater drains.
7. These are also extensively used in the plumbing industry.

Summary

As mentioned above, the globe valve is used to cut off the pipeline flows. The regulating performance of this valve is good. The opening size is small, the closing time is short, and maintenance is easy for the globe valve. This valve body sealing performance is good, and the service life span is prolonged.

The body design of the globe valve is more complex; thus, the energy consumption and the flow resistance are large. It is helpful for media such as oil products, steam, and non applicable fluids with large viscosity.